From ddf4a69b083416fa0e626f591b3b425085656531 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 10 Jan 2007 15:39:51 +0100 Subject: [PATCH] [PATCH] Fix standard deviation calculation Signed-off-by: Jens Axboe --- stat.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/stat.c b/stat.c index a84f28a5..6e7c2357 100644 --- a/stat.c +++ b/stat.c @@ -298,11 +298,11 @@ static int calc_lat(struct io_stat *is, unsigned long *min, unsigned long *max, if (n <= 1.0) return 1; - o = (double) is->val_sq - ((*mean * *mean) / n); + o = ((double) is->val_sq - (*mean * is->val)) / n; if (o < 0.0) *dev = -1.0; else - *dev = sqrt(o / (n - 1.0)); + *dev = sqrt(o); return 1; } -- 2.25.1